Blackjack

Where the edge comes from

You and the dealer both try to get closer to 21 than the other without going over. The dealer's play is fixed by the house: hit until 17, then stand. Yours is up to you, and you act first.

That last part is the whole edge. If you bust, you lose, and you lose even when the dealer busts afterwards. Every other rule at the table, from the 3 to 2 on a blackjack to doubling and splitting, is there to give some of that back to you. With good rules and correct play, it gives most of it back, and the house is left with something around half a percent. With bad rules or loose play, it doesn't.

3 to 2 or 6 to 5

A blackjack, an ace and a ten-value card as your first two cards, has always paid 3 to 2. A lot of tables now pay 6 to 5, and the sign often says "blackjack pays" in large letters with the ratio small underneath.

The difference is easy to work out. On a $10 bet, 3 to 2 pays $15 and 6 to 5 pays $12, so you lose $3, three-tenths of your bet, every time you get a natural. In a six-deck shoe the chance of a natural is about 4.75 percent, which is 2 times 24 aces in 312 cards times 96 tens in the 311 left (about one hand in 21). Three-tenths of a bet on one hand in 21 comes to about 1.4 percent of everything you bet.

That is a lot. It can turn a half-percent game into a game near 2 percent, which is more than the banker or the player at baccarat. I wouldn't play 6 to 5 at all. Walk to the next table or the next casino, and if nobody in town pays 3 to 2, play something else.

The rules on the felt

The other rules move the price less, but they add up, and most are printed on the layout or the sign.

Whether the dealer hits or stands on a soft 17 (a 17 counting an ace as 11) is the one I'd check first. "Dealer hits soft 17" helps the house by about two-tenths of a percent, because the dealer gets a second chance to improve a hand that would otherwise stand. Fewer decks help you a little, being allowed to double after you split helps you, and being allowed to surrender half your bet on a bad hand helps you if you use it properly. A table that offers all the good rules and pays 3 to 2 is worth looking for, and a table that has none of them is the casino telling you what it thinks of the players who sit there.

Basic strategy

For every total you can hold against every card the dealer can show, there is one play that loses least or wins most over time. That set of plays is called basic strategy, and it was worked out decades ago. It fits on a card the size of your hand (if you want to use one at the table, I'd ask the dealer first).

A few of the plays matter more than the rest, because they are the ones people get wrong by feel.

• Always split aces and eights. A pair of eights is 16, the worst total in the game, and two hands starting on 8 are better than one stuck on 16.
• Never split tens. Twenty is a winning hand; don't break it up.
• Against a dealer's 2 through 6, stand on 13 to 16 and let the dealer take the risk of busting. Against a 7 or higher, hit them.
• Double down on 11 against most of the dealer's cards. It is the best spot in the game to get more money down.

Everything else is on the card. Most of what players lose at blackjack beyond the edge goes on plays that feel right: standing on 16 against a 10 because hitting feels worse, or never doubling because it feels greedy. Each of those costs a little on every hand it comes up, and the hands come up all night.

Insurance

When the dealer shows an ace, you will be offered insurance, a side bet that the dealer has a ten underneath. It pays 2 to 1. Four of the thirteen card ranks are worth ten (the ten, jack, queen and king), so with no other information it wins 4 times in 13 and loses 9. Four wins at 2 to 1 is 8 units, against 9 lost, so you give up 1 in every 13, about 7.7 percent.

That is a bad bet, and "even money" on your own blackjack against a dealer's ace is the same bet under another name. I'd decline both every time. The only players who should consider insurance are counting cards and know the shoe is rich in tens.

Counting, shuffles and screens

Card counting works because the cards left in the shoe change the odds, and a shoe full of tens and aces is good for the player. Casinos know it. They watch for it, and they use more decks, shuffle early or deal from continuous shufflers to make it harder. An online blackjack game run by a random number generator shuffles for every hand, so there is nothing to count. The rules on whether and how you can play online depend on where you live.

Side bets at the blackjack table, the ones on pairs or poker hands made with the dealer's card, almost always cost far more than the game itself. I'd leave them alone.

Learn the card, find a table paying 3 to 2, and set your bet so a bad shoe doesn't hurt. Blackjack is cheap if you let it be. If it stops being cheap in other ways, read responsible gambling. The full prices for every game are on the house edge page.